The correct render sampling amount in the render properties tab. Is there a right or wrong amount?
There is no right or wrong. 

A higher number of samples will result on a cleaner picture, but takes longer to render. Clean image in cycles is usually between 200 and 500 samples, sometimes even higher numbers are needed.

A lower number will show some noise, but will render faster.

The correct number is the one that works for you: Is the level of noise tolerable? Can you live with it vs the time needed to render in higher quality?